Development of a selective culture medium for primary isolation of the main Brucella species
Fecha
2011Autor
Versión
Acceso abierto / Sarbide irekia
Tipo
Artículo / Artikulua
Versión
Versión publicada / Argitaratu den bertsioa
Impacto
|
10.1128/jcm.02301-10
Resumen
Bacteriological diagnosis of brucellosis is performed by culturing animal samples directly on both Farrell
medium (FM) and modified Thayer-Martin medium (mTM). However, despite inhibiting most contaminating
microorganisms, FM also inhibits the growth of Brucella ovis and some B. melitensis and B. abortus strains. In
contrast, mTM is adequate for growth of all Brucella species but only partiall ...
[++]
Bacteriological diagnosis of brucellosis is performed by culturing animal samples directly on both Farrell
medium (FM) and modified Thayer-Martin medium (mTM). However, despite inhibiting most contaminating
microorganisms, FM also inhibits the growth of Brucella ovis and some B. melitensis and B. abortus strains. In
contrast, mTM is adequate for growth of all Brucella species but only partially inhibitory for contaminants.
Moreover, the performance of both culture media for isolating B. suis has never been established properly. We
first determined the performance of both media for B. suis isolation, proving that FM significantly inhibits B.
suis growth. We also determined the susceptibility of B. suis to the antibiotics contained in both selective media,
proving that nalidixic acid and bacitracin are highly inhibitory, thus explaining the reduced performance of
FM for B. suis isolation. Based on these results, a new selective medium (CITA) containing vancomycin,
colistin, nystatin, nitrofurantoin, and amphotericin B was tested for isolation of the main Brucella species,
including B. suis. CITA’s performance was evaluated using reference contaminant strains but also field
samples taken from brucella-infected animals or animals suspected of infection. CITA inhibited most contaminant
microorganisms but allowed the growth of all Brucella species, to levels similar to those for both the
control medium without antibiotics and mTM. Moreover, CITA medium was more sensitive than both mTM
and FM for isolating all Brucella species from field samples. Altogether, these results demonstrate the adequate
performance of CITA medium for the primary isolation of the main Brucella species, including B. suis. [--]
Materias
Brucella species,
Farrell medium (FM),
Modified Thayer-Martin medium (mTM),
CITA
Editor
American Society for Microbiology
Publicado en
Journal of Clinical Microbiology, Apr. 2011, Vol. 49, No. 4, p. 1458–1463
Departamento
Universidad Pública de Navarra/Nafarroako Unibertsitate Publikoa. IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua
Versión del editor
Entidades Financiadoras
This work was supported in part by MICINN-CICYT, Spain
(AGL2008-04514-C03-01 and AGL2010-20247), and by the joint Costa
Rica-Spain Bilateral Cooperation (CRUSA-CSIC) (2008CR0006).
Contract support for P.M.M. from the Instituto Nacional de Investigaciones
Agrarias (INIA) of Spain (DR08-0064) and the Grupo Consolidado
de Brucelosis (A-14) of the Arago´n Government is also gratefully
acknowledged.